yeah its hard to say... I would imagine most companies could create new stock to sale in order to cover the costs? I was mostly thinking about creating liquidity for those who want to sell existing stock, more than raising from sale of new stock .

In freedom, liquidity is plentiful. Every company is public if every employee is allowed to sell their stock in the open market. It is precisely regulation that creates private markets. Do without and you will cheaply have an infinite Amount of public companies, without the significant expenditures of dues to wall street.

How expensive?

I once read about 10% of the company, but i wouldn't bet on that memory.

It still requires banks, companies, lawyers, accountants, etc. Its in the millions for sure.